Adhesive proteins of marine fouling organisms (e.g., mussels, hydroids, or tubeworms) have attracted considerable interest because of their superior adhesion properties, including rapidity, strength, and versatility, under dry or wet conditions. One of the common structural elements contributing to the adhesive properties of these marine organisms is the incorporation of the catecholic amino acid 3,4-dihydroxy-L-phenylalanine (DOPA) into the adhesive proteins. Catecholic moieties in DOPA form strong coordination complexes with a host of metal ions, and can form covalent crosslinks in an oxidative environment. These moieties are thus responsible for the excellent wet adhesion properties of marine organisms.
Synthetic polymers incorporating catecholic functionalities for use as adhesives are therefore desirable. However, many synthetic challenges exist to access such artificial systems, including the difficulty in preparation of polymers including sensitive catecholic moieties. For example, unprotected catechols can irreversibly crosslink in air at neutral or basic pH, which can limit the shelf life of such materials. Furthermore, existing polymers are made from expensive starting materials. Materials and methods for making adhesive polymers having desirable adhesive properties are therefore needed.